The effect of the duration of malnutrition on erythrocyte insulin binding and carbohydrate tolerance in rats - abstract

ABSTRACT

To further investigate the effect of malnutrition on carbohydrate metabolism, we have examined the binding of insulin to its receptor in a rat model. The erythrocytes of malnourished animals bound less insulin than controls (6.4 percent vs 17 percent respectively, p<0.01, at 10 days post-weaning, pw). In the later stages of malnutrition (20 days pw), insulin-binding was significantly less than in the early stage (5 days pw) 2.7 percent vs 14.7 percent, p<0.01 respectively). The decreased in binding was also due to decreased receptor affinity in the malnourished compared to the control (0.54 Ke x 10(to 8 power)/M vs 1.4 Ke x 10(to 8 power/M, p<0.01, at 10 days pw). There was no significant difference between the number ob receptors in malnourished and control states. The malnourished animals became insulin-resistant, with a diminished glucose tolerance and a lowered insulin to glucose ratio. Insulin release was also presumably impaired as the malnourished animals had a lowered plasma insulin concentration compared to the controls of the same age (8 æU/ml vs 15.3 æU/ml, p0.05; 10 days pw). In the control animals, the plasma insulin levels increased with age from 8.1 æU/ml at weaning to 27.5 æU/ml (p<0.05) while increase in plasma insulin values shown by the malnourished was not statistically different (10.34æU/ml, 20 days pw). There was an inverse relationship between plasma insulin levels and insulin-binding as the control animals increased in age. The extent and the duration of manutrition adversely affects the binding of insulin to its receptor. This would contributed to the glucose intolerance characteristic of malnurtition (AU)